Patent application title: Micro-actuator having at least one segmented flexible side arm, and method of making the same

Abstract:

Certain example embodiments described herein relate to a micro-actuator
for use with an HGA and/or disk drive device. A substantially U-shaped
frame may include a cavity capable of receiving a slider. The frame may
include two segmented, flexible side arms and a bottom support arm at
least partially defining the cavity. Each segmented side arm may have a
PZT element mounted on an outer surface thereof facing away from the
cavity, and each may include a lower portion proximate to the bottom
support arm and an upper portion disposed at an end opposing the bottom
support arm. The lower portion and the upper portion may be at least
partially separated by a gap. Accordingly, micro-actuators having better
resonance and servo performance, reduced difficulties associated with the
slider/micro-actuator mounting process, and/or better shock performance
may be provided.

Claims:

1. A micro-actuator, comprising:a substantially U-shaped frame including a
cavity capable of receiving a slider, the frame including two side arms
and a bottom support arm at least partially defining the cavity;wherein
each side arm has a PZT element mounted on an outer surface thereof
facing away from the cavity; and,wherein each side arm includes a lower
portion proximate to the bottom support arm and an upper portion disposed
at an end opposing the bottom support arm, the lower portion and the
upper portion being at least partially separated by a gap.

2. The micro-actuator of claim 1, wherein the gap of each side arm
completely separates the upper portion and the lower portion of each
corresponding side arm.

3. The micro-actuator of claim 1, further comprising a protrusion
protruding from the bottom support arm into the cavity.

4. The micro-actuator of claim 3, wherein the protrusion at least
partially defines two recessions, each recession being located between
the protrusion and the lower portions of each side arm.

5. The micro-actuator of claim 1, wherein the micro-actuator is suitable
for being disposed on a suspension tongue, and wherein a slider inserted
into the cavity is situated so that a gap between the slider and the
suspension tongue is at least partially filled in.

6. The micro-actuator of claim 1, further comprising an upper support arm
connecting the upper portions of each side arm.

7. The micro-actuator of claim 6, wherein the bottom support arm and the
upper support arm are substantially cradle-shaped such that the slider is
capable of being located within the cradle.

8. A head gimbal assembly, comprising:a suspension configured to support
on a tongue region thereof a micro-actuator and a slider, the suspension
comprising a hinge coupled with a load beam and a base plate;wherein the
micro-actuator comprises a substantially U-shaped frame including a
cavity capable of receiving the slider, the frame including two side arms
and a bottom support arm at least partially defining the cavity;wherein
each side arm has a PZT element mounted on an outer surface thereof
facing away from the cavity; and,wherein each side arm includes a lower
portion proximate to the bottom support arm and an upper portion disposed
at an end opposing the bottom support arm, the lower portion and the
upper portion being at least partially separated by a gap.

9. The head gimbal assembly of claim 8, wherein the gap of each side arm
completely separates the upper portion and the lower portion of each
corresponding side arm.

10. The head gimbal assembly of claim 8, further comprising a protrusion
protruding from the bottom support arm into the cavity.

11. The head gimbal assembly of claim 10, wherein the protrusion at least
partially defines two recessions, each recession being located between
the protrusion and the lower portions of each side arm.

12. The head gimbal assembly of claim 8, wherein a slider inserted into
the cavity is situated so that a gap between the slider and the
suspension tongue is at least partially filled in.

13. The head gimbal assembly of claim 8, further comprising an upper
support arm connecting the upper portions of each side arm.

14. The head gimbal assembly of claim 13, wherein the bottom support arm
and the upper support arm are substantially cradle-shaped such that the
slider is capable of being located within the cradle.

15. A disk drive device, comprising:a head gimbal assembly carrying a
slider and a micro-actuator;a drive arm connected to the head gimbal
assembly;a disk; and,a spindle motor operable to spin the disk,wherein
the micro-actuator comprises a substantially U-shaped frame including a
cavity capable of receiving a slider, the frame including two side arms
and a bottom support arm at least partially defining the cavity;wherein
each side arm has a PZT element mounted on an outer surface thereof
facing away from the cavity; and,wherein each side arm includes a lower
portion proximate to the bottom support arm and an upper portion disposed
at an end opposing the bottom support arm, the lower portion and the
upper portion being at least partially separated by a gap.

16. The disk drive device of claim 15, wherein for gap of each side arm
completely separates the upper portion and the lower portion of each
corresponding side arm.

17. The disk drive device of claim 15, further comprising a protrusion
protruding from the bottom support arm into the cavity.

18. The disk drive device of claim 17, wherein the protrusion at least
partially defines two recessions, each recession being located between
the protrusion and the lower portions of each side arm.

19. The disk drive device of claim 15, wherein the micro-actuator is
suitable for being disposed on a suspension tongue, and wherein a slider
inserted into the cavity is situated so that a gap between the slider and
the suspension tongue is at least partially filled in.

20. The disk drive device of claim 15, further comprising an upper support
arm connecting the upper portions of each side arm.

21. The micro-actuator of claim 20, wherein the bottom support arm and the
upper support arm are substantially cradle-shaped such that the slider is
capable of being located within the cradle.

22. A method of making a micro-actuator, comprising:connecting two side
portions around one or more center support portions and connecting a PZT
element to an outer side of each side portion to form a large
structure;exposing the large structure to high-temperature firing;
and,cutting the large structure into at least one micro-actuator,wherein
the at least one micro-actuator comprises a substantially U-shaped frame
including a cavity capable of receiving a slider, the frame including two
side arms and a bottom support arm at least partially defining the
cavity,wherein each side arm includes a lower portion proximate to the
bottom support arm and an upper portion disposed at an end opposing the
bottom support arm, the lower portion and the upper portion being at
least partially separated by a gap.

23. The method of claim 22, further comprising disposing two spacer
portions between the side portions and the center support portion.

24. The method of claim 22, further comprising at least partially mounting
the at least one micro-actuator onto a head gimbal assembly.

25. The method of claim 24, further comprising installing the head gimbal
assembly into a disk drive device.

Description:

FIELD OF THE INVENTION

[0001]The example embodiments herein relate to information recording disk
drive devices and, more particularly, to a micro-actuator for use with an
HGA and/or disk drive device with the micro-actuator having segmented
flexible side arms and/or having a reduced gap between the slider and
suspension tongue, and/or methods of making the same.

BACKGROUND OF THE INVENTION

[0002]One known type of information storage device is a disk drive device
that uses magnetic media to store data and a movable read/write head that
is positioned over the media to selectively read from or write to the
disk.

[0003]Consumers are constantly desiring greater storage capacity for such
disk drive devices, as well as faster and more accurate reading and
writing operations. Thus, disk drive manufacturers have continued to
develop higher capacity disk drives by, for example, increasing the
density of the information tracks on the disks by using a narrower track
width and/or a narrower track pitch. However, each increase in track
density requires that the disk drive device have a corresponding increase
in the positional control of the read/write head in order to enable quick
and accurate reading and writing operations using the higher density
disks. As track density increases, it becomes more and more difficult
using known technology to quickly and accurately position the read/write
head over the desired information tracks on the storage media. Thus, disk
drive manufacturers are constantly seeking ways to improve the positional
control of the read/write head in order to take advantage of the
continual increases in track density.

[0004]One approach that has been effectively used by disk drive
manufacturers to improve the positional control of read/write heads for
higher density disks is to employ a secondary actuator, known as a
micro-actuator, that works in conjunction with a primary actuator to
enable quick and accurate positional control for the read/write head.
Disk drives that incorporate micro-actuators are known as dual-stage
actuator systems.

[0005]Various dual-stage actuator systems have been developed in the past
for the purpose of increasing the access speed and fine tuning the
position of the read/write head over the desired tracks on high density
storage media. Such dual-stage actuator systems typically include a
primary voice-coil motor (VCM) actuator and a secondary micro-actuator,
such as a PZT element micro-actuator. The VCM actuator is controlled by a
servo control system that rotates the actuator arm that supports the
read/write head to position the read/write head over the desired
information track on the storage media. The PZT element micro-actuator is
used in conjunction with the VCM actuator for the purpose of increasing
the positioning access speed and fine tuning the exact position of the
read/write head over the desired track. Thus, the VCM actuator makes
larger adjustments to the position of the read/write head, while the PZT
element micro-actuator makes smaller adjustments that fine tune the
position of the read/write head relative to the storage media. In
conjunction, the VCM actuator and the PZT element micro-actuator enable
information to be efficiently and accurately written to and read from
high density storage media.

[0006]One known type of micro-actuator incorporates PZT elements for
causing fine positional adjustments of the read/write head. Such PZT
micro-actuators include associated electronics that are operable to
excite the PZT elements on the micro-actuator to selectively cause
expansion and/or contraction thereof. The PZT micro-actuator is
configured such that expansion and/or contraction of the PZT elements
causes movement of the micro-actuator which, in turn, causes movement of
the read/write head. This movement is used to make faster and finer
adjustments to the position of the read/write head, as compared to a disk
drive unit that uses only a VCM actuator. Exemplary PZT micro-actuators
are disclosed in, for example, JP 2002-133803; U.S. Pat. Nos. 6,671,131
and 6,700,749; and U.S. Publication No. 2003/0168935, the contents of
each of which are incorporated herein by reference.

[0007]FIG. 1 illustrates a conventional disk drive unit and shows a
magnetic disk 101 mounted on a spindle motor 102 for spinning the disk
101. A voice coil motor arm 104 carries a head gimbal assembly (HGA) that
includes a micro-actuator with a slider 103 incorporating a read/write
head. A voice-coil motor (VCM) is provided for controlling the motion of
the motor arm 104 and, in turn, controlling the slider 103 to move from
track to track across the surface of the disk 101, thereby enabling the
read/write head to read data from or write data to the disk 101.

[0008]Because of the inherent tolerances (e.g., dynamic play) of the VCM
and the head suspension assembly, the slider cannot achieve quick and
fine position control, which adversely impacts the ability of the
read/write head to accurately read data from and write data to the disk
when only a servo motor system is used. As a result, a PZT
micro-actuator, as described above, is provided in order to improve the
positional control of the slider 103 and the read/write head. More
particularly, the PZT micro-actuator corrects the displacement of the
slider on a much smaller scale, as compared to the VCM, in order to
compensate for the resonance tolerance of the VCM and/or head suspension
assembly. The micro-actuator enables, for example, the use of a smaller
recording track pitch, and can increase the "tracks-per-inch" (TPI) value
for the disk drive unit, as well as provide an advantageous reduction in
the head seeking and settling time. Thus, the PZT micro-actuator enables
the disk drive device to have a significant increase in the surface
recording density of the information storage disks used therein.

[0009]FIG. 2a is a partial perspective view of an HGA 277 having a
conventionally designed micro-actuator, FIG. 2b is a partial perspective
view of the tongue region of the HGA of FIG. 2a, and FIG. 2c illustrates
how a slider and micro-actuator conventionally are mounted to each other.
With respect to FIGS. 2a-c, a conventional PZT micro-actuator 205
comprises a ceramic U-shaped frame 297. The frame 297 comprises two
ceramic beams 207, each of which has a PZT element (not labeled) mounted
thereon for actuation. The PZT micro-actuator 205 is operably coupled to
a suspension 213, and there are multiple (e.g., three) electrical
connection balls 209 (formed by, for example, gold ball bonding (GBB) or
solder ball bonding (SBB)) to operably couple the micro-actuator 205 to
the suspension traces 210 on one side of each of ceramic beam 207. In
addition, there are multiple (e.g., four) metal balls 208 (formed by, for
example, GBB or SBB) to operably couple the slider 203 to the suspension
traces 210 for connection with read/write transducers (not shown). The
micro-actuator 205 is mounted to the suspension tongue by the bottom arm
of the frame 297, and the slider 203 is at least partially mounted
between the two side arms 207 of the micro-actuator 205.

[0010]The slider 203 is connected (e.g. bonded using epoxy dots 212) to
the two ceramic beams 207 at points 206 proximate to the opening of the
U-shaped frame. The frame 297 is shaped like a hollow rectangular
structure for receiving the slider 203. The bottom of the frame 297 is
attached to the suspension tongue region of the suspension. The slider
203 and the beams 207 are not directly connected to the suspension and
thus may move freely with respect to the suspension.

[0011]When an actuating power is applied through the suspension traces
210, the PZT pieces on the ceramic beams 207 will expand and/or contract,
causing the two ceramic beams 207 to bend in a common lateral direction.
The bending causes a shear deformation of the frame 297, whereby its
shape resembles a parallelogram. The slider 203 undergoes a lateral
translation because it is attached to the moving side(s) of the
parallelogram. Thus, a fine head position adjustment can be attained.

[0012]Unfortunately, translation of the slider 203 may generate a lateral
inertial force that causes a suspension vibration resonance that has the
same or similar resonance effect as shaking the suspension base plate.
This will affect the dynamic performance of the HGA and reduce the servo
bandwidth and the capacity of the HDD. In particular, referring to FIG.
3a, which is a typical prior art micro-actuator design, the U-shaped
micro-actuator 205 is at least partially mounted on the suspension
tongue. When the micro-actuator 205 is operated, the two side arms 307a,
307b will bend outwardly. When one side arm 307a bends along the
direction 300a, it will generate a reaction force Fa in the bottom arm
which is mounted on the suspension tongue. This reaction force Fa will
transfer to the suspension and generate a vibration which have the same
or similar effect as shaking the suspension base plate. Similarly, when
the other side arm 307b bends along the direction 300b, it will generate
a reaction force Fb in the bottom arm and this reaction force Fb also
will transfer to the suspension and generate a vibration which have the
same or similar effect as shaking the suspension base plate.

[0013]As shown in FIG. 3b, which shows the resonance characteristics of
certain prior art micro-actuator designs, line 301 represents a resonance
curve when the suspension base plate is shaken, and line 302 represents a
resonance curve when the micro-actuator 205 of FIG. 3a is excited. As can
be appreciated from FIG. 3b, under a frequency of 20K, there are several
large peaks and valleys in the suspension frequency response, which
indicates poor resonance characteristics.

[0014]Thus it will be appreciated that there is a need in the art for an
improved micro-actuator, HGA, and/or disk drive device, and/or methods of
making the same.

SUMMARY OF THE INVENTION

[0015]One aspect of certain example embodiments described herein relates
to a micro-actuator having a flexible side arm capable of causing
displacement.

[0016]Another aspect of certain example embodiments described herein
relates to a micro-actuator having a reduced and/or eliminated gap
between the slider and the suspension tongue.

[0018]According to certain example embodiments, a micro-actuator is
provided. A substantially U-shaped frame may include a cavity capable of
receiving a slider. The frame may include two side arms and a bottom
support arm at least partially defining the cavity. Each side arm may
have a PZT element mounted on an outer surface thereof facing away from
the cavity. Each side arm may include a lower portion proximate to the
bottom support arm and an upper portion disposed at an end opposing the
bottom support arm, with the lower portion and the upper portion being at
least partially separated by a gap.

[0019]According to certain other example embodiments, a head gimbal
assembly is provided. A suspension may be configured to support on a
tongue region thereof a micro-actuator and a slider. The suspension may
comprise a hinge coupled with a load beam and a base plate. The
micro-actuator may comprise a substantially U-shaped frame including a
cavity capable of receiving a slider. The frame may include two side arms
and a bottom support arm at least partially defining the cavity. Each
side arm may have a PZT element mounted on an outer surface thereof
facing away from the cavity. Each side arm may include a lower portion
proximate to the bottom support arm and an upper portion disposed at an
end opposing the bottom support arm, with the lower portion and the upper
portion being at least partially separated by a gap.

[0020]According to still other example embodiments, a disk drive device is
provided. A head gimbal assembly may carry a slider and a micro-actuator.
A drive arm may be connected to the head gimbal assembly. A disk and a
spindle motor operable to spin the disk also may be provided. The
micro-actuator may comprise a substantially U-shaped frame including a
cavity capable of receiving a slider. The frame may include two side arms
and a bottom support arm at least partially defining the cavity. Each
side arm may have a PZT element mounted on an outer surface thereof
facing away from the cavity. Each side arm may include a lower portion
proximate to the bottom support arm and an upper portion disposed at an
end opposing the bottom support arm, with the lower portion and the upper
portion being at least partially separated by a gap.

[0021]Yet further example embodiments provide a method of making a
micro-actuator. Two side portions may be connected around one or more
center support portions, and a PZT element may be connected to an outer
side of each side portion to form a large structure. The large structure
may be exposed to high-temperature firing. The large structure may be cut
into at least one micro-actuator. The at least one micro-actuator may
comprise a substantially U-shaped frame including a cavity capable of
receiving a slider, with the frame including two side arms and a bottom
support arm at least partially defining the cavity. Each side arm may
include a lower portion proximate to the bottom support arm and an upper
portion disposed at an end opposing the bottom support arm, the lower
portion and the upper portion being at least partially separated by a
gap.

[0022]In certain non-limiting example embodiments, the gap of each side
arm may completely separate the upper portion and the lower portion of
corresponding side arm. Also, the micro-actuator of certain example
embodiments may further include a protrusion at least partially defining
one or more recessions located between the protrusion and the lower
portions of each side arm. In addition to the bottom support arm, an
upper support arm may be provided in certain example embodiments, with
both the bottom support arm and the upper support arm being substantially
cradle-shaped such that the slider is capable of being located within the
cradle.

[0023]Other aspects, features, and advantages of this invention will
become apparent from the following detailed description when taken in
conjunction with the accompanying drawings, which are a part of this
disclosure and which illustrate, by way of example, principles of this
invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]The accompanying drawings facilitate an understanding of the various
embodiments of this invention. In such drawings:

[0025]FIG. 1 is a partial perspective view of a conventional disk drive
unit;

[0026]FIG. 2a is a partial perspective view of an HGA having a
conventionally designed micro-actuator;

[0027]FIG. 2b is a partial perspective view of the tongue region of the
HGA of FIG. 2a;

[0028]FIG. 2c illustrates how a slider and micro-actuator conventionally
are mounted to each other;

[0042]FIGS. 9a-d structurally show an illustrative process for creating
micro-actuators according to certain example embodiments;

[0043]FIG. 9e is a flowchart of an illustrative process for creating
micro-actuators, in accordance with an example embodiment;

[0044]FIG. 10 is an enlarged view of another micro-actuator structure, in
accordance with an example embodiment; and,

[0045]FIG. 11 is a perspective view of an assembled hard disk drive, in
accordance with an example embodiment.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

[0046]Certain example embodiments disclosed herein relate to
micro-actuators, HGAs, and disk drive devices including a micro-actuator
having at least one flexible side arm and/or having a reduced (or in
certain example embodiments, eliminated) gap between the slider and the
suspension. Certain example embodiments disclosed herein may help to
provide better resonance and servo performance, reduce the difficulties
associated with the slider/micro-actuator mounting process, and/or
provide better shock performance. For example, current micro-actuators
are typically substantially U-shaped and have a parallel gap between the
micro-actuator and the suspension, whereas the micro-actuators of certain
example embodiments have a space in at least one side arm of the U-shaped
frame and have a reduced gap between the slider and the suspension.
Certain example embodiments are well-suited for high RPM disk drive
devices, although they may be implemented in any type of disk drive
device.

[0047]FIG. 4a is a partial perspective view of an HGA, in accordance with
an example embodiment. A suspension 430 supports a micro-actuator 401
having an associated slider 203. The suspension 430 comprises a base
plate 411, a hinge 412, a flexure 410, and a load beam 414. The outer
traces 406 in the flexure 410 operably couple the read/write head of the
slider 203 and the pads 415. The inner traces 405 in the flexure 410
operably couple the micro-actuator 401 with the pads 415. The pads 415
are operably coupled to the control system of the HDD.

[0048]FIG. 4b is a detailed partial perspective view of the tongue region
of the HGA of FIG. 4a, in accordance with an example embodiment. The
micro-actuator 401 is mounted on the suspension tongue region, and a
slider 203 is at least partially mounted to the micro-actuator 401. There
are multiple connection balls 407 (e.g. 6 balls as shown in FIG. 4b,
although the present invention is not limited to any particular number of
connections and/or connection balls) operably coupling the slider 203 to
the suspension traces 406. There are two curves 404 in the outer traces
406. These curves help to release stresses related to the stiffness of
the outer traces 406 during the operation of the micro-actuator 401, thus
helping to make the micro-actuator 401 work more smoothly. Additional
connection balls 408 operably couple the micro-actuator 401 to the
suspension traces 405.

[0049]FIG. 4c is an enlarged view of the micro-actuator 401 of FIGS. 4a
and 4b, in accordance with an example embodiment. The micro-actuator 401
comprises a bottom support 430 and two segmented side arms. There are two
PZT elements 435 located on the outer surfaces of the two side arms. Each
segmented side arm comprises a lower portion 432 connected to the bottom
support 430 of the micro-actuator 401, as well as an upper portion 433
connected to the PZT element 435. That is, there is a space or gap 431 in
the side arms between the upper portions 433 and the lower portions 432.
As also can be appreciated from FIG. 4c, there are two recessions 436
formed at opposing sides of the bottom support 430 proximate to the slot
for receiving the slider 203. Alternatively or in addition, there is a
protrusion 437 extending from the bottom support 430 forming gaps 436
between the protrusion 436 and the lower portions 432 of the side arms.
There are also two pads 320b at the ends of the outer surface of the two
PZT elements 435 for driving (e.g., electrically driving) the two PZT
elements 435. It has been determined that this arrangement and similar
arrangements help to maintain the flexibility of the two side arms while
also making it better suited for slider displacement.

[0050]FIG. 4d is a side view in the tongue region of an HGA, in accordance
with an example embodiment. FIG. 4d shows a dimple 417 formed on the
suspension load beam 414, which supports the tongue 418 of the suspension
flexure. The dimple 417 may support the center of the back side of the
suspension tongue 418. The support point also may offset the center of
the back side of the suspension tongue 418. The slider 203 is supported
by the two side arms of the micro-actuator 401. The bottom support 430 of
the micro-actuator 401 is mounted on the suspension tongue 418. An epoxy
plot 420 is located on the center region of the suspension tongue 418
which may be used to mount the slider to the suspension tongue 418, A
space 421 is located approximately in the center of the slider, at least
partially separating the slider from the suspension tongue 418. The space
421 is at least partially defined by the epoxy plot 420 and the bottom
arm mounting area. This arrangement allows the slider to rotate
substantially freely when the micro-actuator 401 is operated.

[0051]FIG. 5 is a detailed partial perspective view of the tongue region
of an illustrative HGA that helps to demonstrate the operation of certain
example embodiments. In particular, when the micro-actuator 401 is
operated, one of the side arms shrinks while the other side arm expands
because of the movement generated by one or both of the PZT elements.
Because the back center of the slider is fixed and the top portions of
the two side arms of the micro-actuator 401 are mounted with the two side
surfaces of the slider proximate to its tail edge, the push/pull movement
will cause displacement and thus slider rotation.

[0052]FIG. 6 is a partially exploded view of the tongue region of the HGA
of FIG. 4a, in accordance with an example embodiment. There are two epoxy
plots 606 inserted into the spaces 431 of the two side arms of the
micro-actuator 401. This helps to keep the two arms flexible but also
rigid. This illustrative structure helps to ensure that the
micro-actuator has at least one flexible support arm which facilitates
achieving a large displacement characteristics. This illustrative
structure also helps to improve the shock performance of the
micro-actuator because of the stiffness of the two side arms. The epoxy
plot 602 is applied to the suspension tongue, and the micro-actuator 401
is then mounted to the suspension tongue via the epoxy plot 602. The
epoxy plot 601 is applied to the center of the suspension tongue. The
slider is inserted into the micro-actuator, and the slider is mounted to
the suspension tongue. The epoxy plots 605 may be used for mounting the
slider to the micro-actuator. In another example embodiment, the two
epoxy plots 606 may be inserted into the spaces 431 of the two side arms
of the micro-actuator 401 first, then the two epoxy plots 605 may be
mounted to the slider with the two side arms of the micro-actuator, with
the epoxy 602 and epoxy plot 601 finally applied to the suspension tongue
before the micro-actuator and slider are mounted to the suspension. It
will be appreciated that these and/or other manufacturing processes may
be used to achieve the same or similar HGA structure.

[0053]FIGS. 7a and 7b show techniques for driving micro-actuators, in
accordance with an example embodiment. For example, a sine voltage may be
applied to the micro-actuator having two side arms which have opposed
polarization directions. One of the side arms of the micro-actuator will
shrink, but the other will extend. Because the slider is at least
partially mounted to the two side arms of the micro-actuator and also at
least partially mounted to the suspension tongue, a torque will be
generated, causing slider to rotate against the epoxy plot 601 and
generate a displacement. Because the epoxy plot 601 is located
approximately in the center of the slider's back side, the slider will
rotate approximately around its center. In FIG. 7a, a single wave is
input, whereas when two sine waves having opposite phases are input to
the two PZT elements of the micro-actuator having opposite polarization
directions as shown in FIG. 7b, one side arm of the micro-actuator will
shrink but the other arm will extend, similarly, and a torque will be
generated causing the slider to rotate around its center. FIG. 7c shows
the initial status when no voltage is driving the micro-actuator, and
FIG. 7d shows the rotation of the micro-actuator and the slider
displacement when a voltage is applied.

[0054]FIG. 8a shows resonance testing data for certain example
embodiments. The curve 801 shows an HGA resonance gain when the
suspension base plate is excited, and the curve 802 shows an HGA
resonance gain when the PZT micro-actuator is excited. Because the
micro-actuator moves rotationally, there tends to be a reduced amount of
stress transferred to the suspension. Accordingly, there tends to be a
reduced amount of suspension resonance when the micro-actuator is
operated. Similarly, FIG. 8b shows related HGA resonance phase data for
certain example embodiments. The curve 803 shows Phase vs. Frequency data
when the base place is excited, and the curve 804 shows Phase vs.
Frequency data when the PZT micro-actuator is excited.

[0055]FIGS. 9a-d structurally show an illustrative process for creating
micro-actuators, which may be formed from a ceramic base material (e.g.,
Zirconia or Silicon) according to certain example embodiments. In
particular, FIG. 9a is a partially exploded view illustrating one method
of manufacturing an illustrative micro-actuator, in accordance with an
example embodiment. PZT layers 904a-b may be connected (e.g., laminated)
to a top and bottom sheet 902a-b, respectively. The upper and lower side
arm portions 906a-b and 906a'-b' (which may be formed from a ceramic) may
be connected to the inner portions (which may be formed from a ceramic)
of the top and bottom sheet 902a-b, respectively. Spacer sheets 908a-b
(which also may be formed from a ceramic) may be provided between the
upper and lower side arm portions 906a-b and 906a'-b' and the main body
portion(s) 910a-b. It will be appreciated that the various components of
this structure may be members formed by the connection of one or more
support sheets (e.g., the top or bottom sheet 902a-b, the upper and lower
side arm portions 906a-b or 906a'-b', the spacer sheet 908a-b, the main
body portion 910a-b, each can be separated into two or more layer
sheets), or alternatively may be provided as a single sheet, already
formed with the desired dimensions. Of course, the locations of the side
arm portions, spacer portions, main body portions, etc. may be varied in
certain example embodiments (e.g., the sheet laminating method may vary
in production to produce the final micro-actuator structure).

[0056]After the connection (e.g., lamination) process is completed, the
structure may be subjected to a high-temperature firing. The large
U-shaped box structure of FIG. 9b may be cut (e.g., along the dashed
lines of FIG. 9c) to form multiple, single micro-actuator units 914a-d of
the type 914 shown in FIG. 9d. It will be appreciated that the dashed
lines are provided by way of example and without limitation. For example,
a single large U-shaped box structure may be used to produce more or
fewer cuts in certain example embodiments. Also, it will be appreciated
that the desired depth of the micro-actuators may vary.

[0057]FIG. 9e is a flowchart of an illustrative process for creating
micro-actuators, in accordance with an example embodiment. Multiple
sheets may be laminated in step S902 (e.g., as shown in FIG. 9a), thus
forming a "box" in step S904 (e.g., as shown in FIG. 9b). The laminated
structure may be subjected to a high-temperature firing in step S706. The
pieces may be cut (e.g., along the lines shown in FIG. 9c) to produce
multiple, single micro-actuators (e.g., of the type shown in FIG. 9d) in
step S908. The single micro-actuators may be subjected to testing and
inspection in step S910. Optionally, the single micro-actuators may be
cleaned. Finally, the single micro-actuators may be ready for use.

[0058]FIG. 10 is an enlarged view of another micro-actuator 401'
structure, in accordance with an example embodiment. The micro-actuator
401' comprises a frame (e.g., a metal frame) and two PZT elements 435'.
The metal frame includes a top support and a bottom support 430'. There
are two side arms, each being coupled to one of the two PZT elements
435'. The two side arms comprise a lower portion 432' connected to the
bottom support 430' and an upper portion 433' connected to the upper
support 436'. In certain example embodiments, the upper portions 433' and
upper support 436', as well as the lower portions 432' and lower support
430' may be thought of as forming a cradle for accommodating the slider.
Each side arm has a space 431' formed therein. This space helps to ensure
flexibility for the micro-actuator 401' and provides for advantageous
slider displacement.

[0059]FIG. 11 is a perspective view of an assembled hard disk drive, in
accordance with an example embodiment. In brief, the HDD includes a frame
1101. One or more disks 1102 are spun by a spindle motor 1203. A VCM 1104
controls the slider 1105 that flies over the disk 1102. The slider 1105
may be inserted into a micro-actuator frame (not shown), designed in
accordance with any example embodiment disclosed herein. One of ordinary
skill in the art will clearly understand the operation of the HDD of FIG.
11, and further details are omitted to avoid confusion.

[0060]It will be appreciated that the micro-actuator frames described
herein may be formed from any suitable material. By way of example and
without limitation, the micro-actuator frames may be formed from a metal,
a ceramic, or any other suitable material. Additionally, any suitable
type of PZT element may be used, such as, for example, a ceramic PZT, a
thin-film PZT, or a PMN-Pt PZT. Moreover, the PZT element may be a single
layer or a multi-layer PZT element. Finally, it will be appreciated that
in certain example embodiments, the gaps formed in the side arms may
completely separate the upper and lower portions of each side arm.
However, in certain other example embodiments, the gaps may consist of
one or more protrusions and/or recessions to define one or more gaps
between one or more portions of each side arm.

[0061]While the invention has been described in connection with what are
presently considered to be the most practical and preferred embodiments,
it is to be understood that the invention is not to be limited to the
disclosed embodiments, but on the contrary, is intended to cover various
modifications and equivalent arrangements included within the spirit and
scope of the invention.